Paradigm shift of underwater echo sounding technology I—Principle and algorithm

Underwater echo sounding technology was developed 65 years ago and has been applied in various systems such as fishfinder, bathymetry, sonar, side scanning sonar, multi beam echo sounding system, and synthetic aperture sonar. Here, we proudly suggest a new concept that may change the history of underwater echo sounding technology, the “Paradigm Shift.” In the conventional system, the transmitting signal is transmitted after receiving the target signal, e.g., a bottom echo. Therefore, the transmission intervals are always longer than the time of the round trip distance to the target divided by the underwater sound velocity. On the other hand, by adapting our new “Paradigm Shift” into the system, the transmission intervals can be decided without depending on a target and it will be possible to conduct a bathymetry survey that transmits 100 times per second. The system was tested and confirmed in the actual sea trial. This new concept, the “Paradigm-Shift-Echosounder” ( PSE ), utilizes the 7th order and 127 kinds of Gold code sequence signals. Different code of Gold code signals will be transmitted in each transmission, and receiving signals will be identified by the correlation of the 127 kinds of Gold code sequences of different transmission signals.